This study aims to assess the applicability of Miller and Modigliani’s Dividend Irrelevance Theory in Vietnam and Singapore from 2018 to 2022. By comparing and contrasting results from the two markets, the research seeks to offer insights into potential similarities and differences, enriching academic understanding while providing valuable, updated information for executives and investors for informed dividend and investment decision-making. Using data from the VN30 index of Vietnam and STI index of Singapore, including variables such as stock price, dividends per share, earnings per share, and total assets, the study employs regression analysis with fixed effects models to examine the relationship between dividends and firm values. The analysis indicates a significant relationship between a firm’s dividend policy and its market value, though the impact is negative in Vietnam but positive in Singapore. Additionally, earnings per share is found to positively affect share prices in both markets. As such, the validity of Miller and Modigliani’s Dividend Irrelevance proposition during the study period is challenged.